Method for ascertaining the nature of subterranean strata.



H. LUWY. METHOD FOR ASGBETAINING THE NATURE OF SUBTERRANBAN STRATA. APPLIOATION FILED APR. 1, 1913.

1,092,065. Patented Mar. 31, 1914.

PATENT OFFICE.

HEINRICH Low, or eo'r'rmourr, GERMANY.

METHOD FOR AS GERTAINING THE NATURE OF SUBTERRANEAN STRATA.

Application filed April 1,

Specification of Letters Patent.

Patented Mar. 31., 1914. 1913. Serial No. 758,262.

To all whom it may concern:

Be it known that I, Dr. HEINRICH Lowr, a subject of the Austro -'Hungarian Emperor, residing at 5 Buhlstrasse, Gottingen, Germany, have invented certain new and useful improvements in Methods for Ascertaining th Nature of Subterranean Strata; and I do herebydeclare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention refers to a method for investigating strata in the vicinity of mines.

I have found by experiment that the capacity and the damping coefficient ofan antenna placed in a mine in the interior of the earth and energized by electrical oscillations is considerably influenced by the properties of the strata which surround the point wherethe antenna is located.

My invention consists in a method for ascertaining the nature of such strata by observing the behavior of such transmitters 'of electric waves.

To reduce my method to practice I determine the normal capacity and the damping coefficient of an antenna adapted to radiate electric waves, 'viz., when the antenna is surrounded by air or other substantially constant medium, and then determine the changes or variations of the capacity and the damping coefficient thereof when the antenna is located in different parts of a mine. By comparing the results of such.

measurements I can arrive at definite conclusions relating to the nature of the surrounding strata. Thus a stratum composed of clay (whose dielectrical constant is 13) interposed in strata consisting of salt (whose dielectrical constant is 6) is revealed by a considerable increase of the capacity of the oscillatory system (confer Ammlen der Physilc 36,1911, p. 125). Instead of observing the capacity it is also suflicient to determine the frequency by means of a wave detector. Likewise the proximity of water and strata containing water can be discovered by the described means, and this is of specific usefulness in salt mines in which'it is of the utmost importance to avoid striking such strata.

The accompanying drawing illustrates the mode of proceeding according to my present invention where the object is to investigate the nature of strata situated in the direction in which a gallery is to be driven.

Figure 1 is a plan section through a gallery showing diagrammatically apparatus and Fig. 2 is a similar plan section with the apparatus placed in a position referring to a subsequent stage of the procedure.

At the end of a gallery G is placed a symmetrical antenna, consisting of two wires A A and A A stretched out horizontally alon the bottom of the gallery. By determining the capacity and the damping c0.- eflicient of this system the nature of the vealed. If the measurement shows that this portion of the surrounding strata does not contain any water, two bore holes 13 and 13,, Fig. 2 are driven sidewise, thus making room for a crosswise spread of the antenna.

bore hole B B and by repeating the same ated in the direction'of advance of'the gallery is ascertained.

The longer the antennae are made the larger is the range investigated and the smaller the number of measurements required. (Confer Flemming Principles of Electric Wave Telegraphy p. 551 and 552.)

Having thu described my invention what I claim is:

- A method for ascertaining the nature of subterranean strata which comprises placing a preliminarily calibrated circuit capahole and determining the variation of its ca acity orits frequency and dampmg ooo cient as compared. with the prior calibration, a

In testimony whereof I have aflixed my signature, in presence of two witnesses.

DR. HEINRICH L6WY.

Witnesses: J

Elvin. ORNsTEIN, Auousrr Foeonn.

rocks on both sides of the gallery is re-.

measurements the nature of the rock situplaced in position for applying my method The antenna A, A is then placed along the ble of electric oscillations in a mine or bore 

